(U//FOUO) We assess that terrorists likely view tactics involving throwing or spraying acids and a variety of chemical liquids, hereafter referred to as a chemical spray and splash attack (CSSA), as a viable tactic to cause injury and disrupt critical infrastructure, judging from open source reporting describing terrorist social media posts and terrorist and violent extremist use of this tactic overseas. An analysis of a small number of incidents described in media reporting revealed that CSSAs are commonly used by criminal actors to further criminal activities and by violent extremist groups overseas to create fear, intimidate, punish, and disfigure individuals and groups that resist their control or ideology in their area of operations; the tactic, however, has rarely been operationalized by actors in the Homeland. We note, however, that homegrown violent extremists (HVEs) and lone offenders likely would find this tactic appealing and could easily adapt it to the Homeland, as it requires no specific technical expertise and the materials most often associated with criminal attack are usually unregulated and widely available.

(U//FOUO) We assess that anarchist extremists, other domestic terrorists (DTs), and criminal actors are the most likely US-based violent extremists to use CSSAs based on our analysis of past and present DT use of this tactic and on open source reporting of unaffiliated criminal actors using acids, toxic industrial chemicals, and other chemical incapacitating agents in attacks in the Homeland. They have used CSSA tactics against law enforcement, institutions, ideological opponents, protesters, and mass gatherings, especially those associated with political or social causes, judging from a body of open source reporting. These actors rarely used CSSAs to cause fatalities, but previous incidents have demonstrated that domestic CSSAs can cause significant bodily harm and disrupt law enforcement and first responder operations.

(U//FOUO) While foreign terrorist organizations (FTO) and violent extremist groups have operationalized CSSA overseas and have made recent calls for such attacks in the Homeland, we lack specific information indicating that HVEs or lone offenders would be receptive to this tactic or would seek to incorporate CSSAs into attacks inside the United States; we assess, however, that many of the factors likely driving criminal use of CSSAs—such as the ability to harm individuals, cause infrastructure disruption, possibly evade capture following an attack, and/or perpetrate repeat attacks—likely would also make this tactic attractive to terrorists, especially violent extremists lacking training, and the access or desire to use explosives or firearms.

(U//FOUO) Strong acids and caustic chemicals are frequently used in CSSAs, but we assess attackers are just as likely to choose other commercially available chemicals such as pepper spray, bleach, ammonia, solvents, and other irritating, foul smelling, or toxic industrial chemicals, based on the variety of materials used for CSSAs domestically and abroad. First responders treating victims of CSSAs may face secondary dermal and inhalation hazards depending on the type of chemicals used.

(U//FOUO) We assess that terrorists likely view tactics involving throwing or spraying acids and a variety of chemical liquids, hereafter called chemical spray and splash attacks (CSSAs), as a viable tactic to cause injury and disrupt critical infrastructure, judging from open source reporting describing terrorist social media posts and terrorist and violent extremist use of this tactic overseas. An analysis of a small number of incidents described in media reporting revealed that CSSAs are commonly used by criminal actors to further criminal activities and by violent extremist groups overseas to create fear, intimidate, punish, and disfigure individuals and groups that resist their control or ideology in their area of operations; the tactic, however, has rarely been operationalized by actors in the Homeland. We note, however, that HVEs and lone offenders likely would find this tactic appealing and could easily adapt it to the Homeland, as it requires no specific technical expertise and the materials most often associated with criminal attack are usually unregulated and widely available.

» (U//FOUO) The Islamic State in Iraq and ash-Sham (ISIS)-linked “Lone Mujihad” channel on the Europe-based messaging application Telegram, as of late 2017, urged US-based ISIS-supporters to attack “unbelievers” with sulfuric acid on public transportation.

» (U) Violent extremists affiliated with ISIS in Iraq and Syria, since at least early 2015, were allegedly smearing or throwing acid in the faces of women from the Iraq-based Yazidi religious minority and Kurdish women who refused to be sex slaves or submit to forced marriages, according to open source reporting. Additionally, ISIS-affiliated violent extremists publicly tortured and executed enemies, traitors, and those they deemed “immoral” by dipping them in vats of nitric acid, according to open source media describing accounts from sources claiming direct access.

» (U) Individuals affiliated with Taliban branches in Afghanistan and Pakistan have thrown acid at young women who refused marriage or allegedly dishonored their family, according to open source media reporting and international aid organizations. Members of both groups continue to openly advocate throwing acid in the faces of young girls who seek “Westernized” education.

(U) In likely unrelated incidents, unknown actors in Germany disrupted air and rail transportation operations by releasing unknown irritating agents—most likely pepper spray—at Hamburg International Airport and on a commuter train in early 2017, according to open source media reports.

…

(U//FOUO) Anarchist Extremists and Other DTs Most Likely US-based Threat Actors to Use CSSAs

(U//FOUO) We assess that anarchist extremists, other DTs, and criminal actors are the most likely US-based criminal actors to use CSSAs based on our analysis of past and present DTs use of this tactic and on open source reporting of unaffiliated criminal actors using acids, toxic industrial chemicals, and other chemical incapacitating agents in attacks in the Homeland. They have used CSSA tactics against law enforcement, institutions, ideological opponents, protesters, and mass gatherings, especially those associated with political or social causes, judging from a body of open source reporting. These actors rarely used CSSAs to cause fatalities, but previous incidents have demonstrated that domestic CSSAs can cause significant bodily harm and disrupt law enforcement and first responder operations.

» (U) On multiple occasions since 2012, state and local law enforcement officials have warned that violent anarchist groups planned to disrupt peaceful protests or political conventions using acid-filled eggs, holiday ornaments, and other objects filled with urine, including squirt guns, according to open source media reports, some citing law enforcement information.